Suzuki M, Kaga K
Department of Otolaryngology, University of Tokyo, Japan.
Hear Res. 1999 Mar;129(1-2):27-34. doi: 10.1016/s0378-5955(98)00214-7.
Cationic polyethyleneimine (PEI) administered intravenously was transported to anionic sites on the capillary and subepithelial basal laminae (BL) in the vestibular labyrinth. Therefore, changes in the PEI distribution on the BL reflect changes in the transport system in the vestibular labyrinth. A 0.1% PEI solution was administered intravenously (7.5 ml/kg) to developing (1, 4, 7, 14 days after birth) and adult rats in order to investigate the development of the macromolecular transport in the ampulla of the semicircular canal as a function of age. After 1 h, the bony labyrinth was removed and embedded in Epoxy resin. Ultrathin sections of the ampulla were then examined with a transmission electron microscope. In the subepithelial BL in the dark cell area and capillary BL in the crista ampullaris, the PEI distribution in both 1- and 4-day-old rats was markedly increased compared to that in either 7-, 14-day or adult rats. In the sensory cells in 1-, 4-day or 7-day-old rats, PEI density and area was significantly greater than in the adult rats. These findings suggest that the macromolecular transport system in the developing rat ampulla becomes mature by 14 days after birth and that the maturation of its transport system in the ampulla is strongly associated with that in the stria vascularis.
静脉注射的阳离子聚乙烯亚胺（PEI）被转运至前庭迷路中毛细血管和上皮下基膜（BL）上的阴离子位点。因此，PEI在基膜上分布的变化反映了前庭迷路中转运系统的变化。为了研究半规管壶腹中大分子转运随年龄的发育情况，将0.1%的PEI溶液静脉注射（7.5 ml/kg）给发育中的（出生后1、4、7、14天）和成年大鼠。1小时后，取出骨迷路并包埋在环氧树脂中。然后用透射电子显微镜检查壶腹的超薄切片。在暗细胞区域的上皮下基膜和壶腹嵴中的毛细血管基膜中，1日龄和4日龄大鼠的PEI分布与7日龄、14日龄大鼠或成年大鼠相比均显著增加。在1日龄、4日龄或7日龄大鼠的感觉细胞中，PEI的密度和面积明显大于成年大鼠。这些发现表明，发育中的大鼠壶腹中的大分子转运系统在出生后14天成熟，并且其壶腹中转运系统的成熟与血管纹中的成熟密切相关。
